Too much Alkalinity up

Causes and cures for cloudy swimming pool water.
Milky pool water, white, pink, brown, purple, black cloudy water.
dogmae
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Too much Alkalinity up

Postby dogmae » Sat 08 May, 2010 17:31

Thanks to Leslie's my Mother put 30 lbs of Alkalinity Up in her pool at once, around 7 PM last night. Today at about 9 AM my father put about 6lbs of soda ash in at once. The filter was running the whole time.

Now at 6 PM the pool is very, very cloudy.

I've read that you are supposed to only use 10lbs of AK Up every 4 hours, is it a big issue that they slammed it all in at once?


What do I need to do to solve it, just let the filter run for a while? Or something more drastic?

It's a DE filter if that matters.


chem geek
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Too much Alkalinity up

Postby chem geek » Sat 08 May, 2010 19:58

30 pounds of Alkalinity Up (sodium bicarbonate; baking soda) in 10,000 gallons would raise the TA by 214 ppm! Even if the pool was larger at 20,000 gallons, that's still over 100 ppm increase in TA which is probably way too much.

6 pounds of Soda Ash (sodium carbonate; washing soda) in 10,000 gallons would also increase TA by 68 ppm and raise the pH from 7.5 to around 9.2, depending on starting TA. Even in 20,000 gallons, this would increase TA by 34 ppm and raise the pH from 7.5 to 8.8 or so.

No wonder you got cloudy water. In fact, you probably got scaling (calcium carbonate precipitate) as well unless your Calcium Hardness (CH) is very low. What a disaster. Are Leslie's a bunch of idiots?

You need to tell me more about your pool such as its size in gallons and the starting TA and pH numbers as well as the Calcium Hardness (CH) and whether the pool is vinyl or plaster or fiberglass. You should probably find out the Cyanuric Acid (CYA) level while you are at it.

In the meantime, I suggest significantly lowering the pH by adding Muriatic Acid, but note that with the very high TA the pH will tend to rise again. To fix this you are either going to have to add very large amounts of Muriatic Acid over time or you're going to have to replace some of the water. If your CYA is high, then diluting the water would be needed anyway.
dogmae
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Too much Alkalinity up

Postby dogmae » Sat 08 May, 2010 20:15

It's an inground gunite pool
As fas as how many gallons it is, I am not quite sure off hand. I think, from what my parents have said before, it is around 30,000 gallons, or so. I do know that the DE filter is 48 sq ft if that helps narrow down the size.

Heres the numbers from Leslie's water analysis. (before they dumped all this in)

Free Available Chlorine 3.0
Water PH 7.0
Total Alkalinity 40
Calcium Hardness 100
Cyanuric Acid 100
Total Dissolved Solids 360
chem geek
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Too much Alkalinity up

Postby chem geek » Sun 09 May, 2010 10:03

OK, then this isn't quite as insane as it first sounded. If the initially measured numbers are correct and if the pool is truly 30,000 gallons (which is quite large -- something like an 18'x40' pool with 8 foot deep end), then 30 pounds of Alkalinity Up plus 6 pounds of pH Up would result in a pH of 7.7 and a TA of 134 ppm with an overall saturation index of -0.13. So that's not terrible.

If the above is correct, then the cloudiness should dissipate and clear up on its own. However, I'd keep the pump on and retest the water, preferably with your own good test kit since the pool store numbers may not be accurate. Get yourself a Taylor K-2006 at a good online price here or the TF-100 kit from tftestkits.net here with the latter kit having more volume of reagents so is roughly comparably priced per test.
Guest

Too much Alkalinity up

Postby Guest » Sun 09 May, 2010 13:56

Thanks for the info.
chem geek
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Too much Alkalinity up

Postby chem geek » Sun 09 May, 2010 16:55

Note that the CYA level of 100 ppm is high and in fact could be higher since most CYA tests only measure up to 100 ppm. The high CYA level will make it harder for the chlorine to prevent algae growth unless you keep the FC proportionately higher. So you'll probably need to do some water dilution to get the CYA lowered and in the meantime keep the FC above 5 ppm at all times using chlorinating liquid or bleach to do so. Do not use stabilized chlorine products (Trichlor or Dichlor) as these will increase the CYA level over time.

The following are chemical facts independent of product concentration or of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

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